Zinc oxide-hydroxyapatite nanocomposite photocatalysts for the degradation of ciprofloxacin and ofloxacin antibiotics

Zinc oxide-hydroxyapatite nanocomposites were prepared from a natural phosphate ore via a solvent-free method and evaluated for the photodegradation of two antibiotics in solution. The in situ growth of ZnO followed by thermal treatment allowed for the formation of photocatalytic nanocrystals homogeneously dispersed in the apatite phase. Nanocomposites exhibited higher rates of sorption of ofloxacin and ciprofloxacin compared to the individual phases. At high ZnO loadings, photodegradation performances of the nanocomposites under UV irradiation were equivalent or greater than that of the photocatalytic particles alone, depending on the considered antibiotic. This dependency reflects distinct degradation pathways that were attributed to different affinities of the antibiotics for the nanocomposite particles. Because of its simplicity and versatility, the here-described approach appears very promising for the development of multifunctional platforms for water remediation.